1. Application of FVCOM to the Gulf of Maine/Georges Bank:
Simulated and Assimilated Modeling Studies of Stratification and Sub-tidal Circulation
Chen, C, H. Liu, R. C. Beardsley, G. Cowles, J. Pringle, R. Schlitz and B. Rothschild

2. Meteorological forcing
GOM/GB MM5
Boundary forcings
Assimilation
Wind stress, heat flux
Real-time tidal forcing
River discharges
Scotian shelf water input
North Atlantic open boundary condition ??
SST
Hydrographic survey CTD
ADCP
Moored current meter data
CODAR??
The FVCOM GOM/GB
Physical Model

3. The Finite-Volume Coastal Ocean Model (FVCOM)
NECE
6 ADCPs
3-6, 1999

4. Re-start with the assimilated field
The 1995 and 1999 Experiments
Run the model with tidal forcing only from December 1-15;
Re-start the model on December 15 with the initial condition of T and S given by December climatologic hydrographic field;
Add real-time wind stress, heat flux, river discharge, etc on January 1
Simulating
Re-start with the assimilated field
January
February
Assimilating:
SST, Current

5. Observed
Calculated
Observed
Calculated M2 N2 S2

6. Observed
Calculated
Observed
Calculated K1 O1

8. The 1995 Simulation and Assimilation

9. Observed Simulated Assimilated
Jan
Feb
March

10. Observed
Simulated
Assimilated
April
May
June

11. Observed Simulated Assimilated
July
Aug
Sept

12. Observed Simulated Assimilated
Oct
Nov
Dec

20. Site: NECE
23 m
99 m
191 m

21. Site: NECE
23 m
99 m
191 m

22. February 1995

23. July 1995

24. The 1999 Summer Simulation and Assimilation

25. Observed
Simulated
Assimilated

26. Observed
Simulated
Assimilated
Times (day) May 1999

27. Site2
Site4
Site6
Observed
Simulated
Assimilation

28. Comparison between observed and simulated currents
at an ADCP site
May 1999

29. Simulated subtidal surface water temperature and currents
May 1999
Simulated subtidal surface water temperature and currents

30. Summary
Both simulation and assimilation clearly show that the seasonal variation of clockwise subtidal gyre on GB and also cyclonic circulation around the Jordon basin. The cyclonic circulation forming around the Jordon basin could cause a significant on-bank water transport to GB during summer.
Good agreement between model-predicted and observed currents was found on the southern flank of GB, but not in the Northeast Channel (NEC). This suggests that the subtidal circulation on GB is mainly controlled by local forcing, while the currents in the eastern GOM/GB are strongly influenced by water input from the Scotian Shelf.
Nudging assimilation is used to merge the model-computed and observed currents in the NEC. This approach produces a more realistic pattern of subtidal currents and on-bank transport on the northeastern flank of GB.